Acids Bases and Salts — Class 10 Chemistry NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 10 Chemistry chapter "Acids Bases and Salts" — 10 important questions with detailed answers for CBSE board exam preparation.
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TL;DR: Free step-by-step NCERT solutions for Class 10 Chemistry chapter "Acids Bases and Salts" — 10 important questions with detailed answers for CBSE board…
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Key Questions Covered:
- A solution turns red litmus blue. What is its nature? What will happen if thi…
- When dilute hydrochloric acid is added to: (a) Magnesium ribbon (b) Sodium ca…
- A student mixes 10 mL of a strong acid (like HCl) with 10 mL of a strong base…
- Why is it advised to use an antacid when someone suffers from indigestion? Ex…
- Why is it recommended to add acid to water, and not water to acid, while dilu…
- What is meant by 'water of crystallisation'? Give two examples of salts that …
- + 4 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| A solution turns red litmus blue. What is its nature? Wha… | ✓ Solved |
| When dilute hydrochloric acid is added to: (a) Magnesium … | ✓ Solved |
| A student mixes 10 mL of a strong acid (like HCl) with 10… | ✓ Solved |
| Why is it advised to use an antacid when someone suffers … | ✓ Solved |
| Why is it recommended to add acid to water, and not water… | ✓ Solved |
| What is meant by 'water of crystallisation'? Give two exa… | ✓ Solved |
Showing 6 of 10 questions
Q1: A solution turns red litmus blue. What is its nature? What will happen if this solution reacts with zinc metal? Write the chemical equation if a reaction occurs.
Step 1: Identify the nature of the solution.
* Acids turn blue litmus red.
* Bases turn red litmus blue.
* Since the solution turns red litmus blue, it is basic in nature.
Step 2: Determine the reaction with zinc metal.
* Bases react with certain active metals (like zinc, aluminium) to produce hydrogen gas and a salt.
* For example, sodium hydroxide (a base) reacts with zinc metal.
Step 3: Write the chemical equation.
* Let's assume the base is Sodium Hydroxide (NaOH).
* Reaction...
Q2: When dilute hydrochloric acid is added to: (a) Magnesium ribbon (b) Sodium carbonate Describe the observations in each case and write the balanced chemical equations.
Case (a): Dilute HCl added to Magnesium ribbon
* Observation: Rapid effervescence (formation of bubbles) will be observed. These bubbles are of hydrogen gas, which burns with a 'pop' sound when a burning splinter is brought near it.
* Chemical Equation: Magnesium metal reacts with dilute hydrochloric acid to produce magnesium chloride (a salt) and hydrogen gas.
Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
Case (b): Dilute HCl added to Sodium carbonate
* Observation: Brisk effervescence (rapid...
Q3: A student mixes 10 mL of a strong acid (like HCl) with 10 mL of a strong base (like NaOH) in a test tube. (a) What will be the colour of the resulting solution if a drop of phenolphthalein indicator is added to it? (b) What will be the pH of the resulting solution? (c) Write the chemical equation for the reaction.
Step 1: Understand the reaction.
* When a strong acid (HCl) reacts with a strong base (NaOH), a neutralisation reaction occurs. If equal volumes and concentrations of a strong acid and strong base are mixed, they completely neutralise each other.
Step 2: Determine the colour with phenolphthalein.
* Phenolphthalein indicator is colourless in acidic and neutral solutions but turns pink in basic solutions.
* Since the resulting solution is neutral (due to complete neutralisation), phenolphth...
Q4: Why is it advised to use an antacid when someone suffers from indigestion? Explain with a suitable chemical reaction.
Step 1: Understand indigestion.
* Our stomach naturally produces hydrochloric acid (HCl) which aids in the digestion of food.
* During indigestion, the stomach produces an excess amount of this acid, leading to discomfort, pain, and irritation (a condition commonly known as acidity).
Step 2: Role of antacids.
* Antacids are mild bases (or alkaline substances). They typically contain compounds like magnesium hydroxide (Mg(OH)₂) or aluminium hydroxide (Al(OH)₃).
Step 3: Chemical reaction a...
Q5: Why is it recommended to add acid to water, and not water to acid, while diluting a concentrated acid?
Step 1: Understand the nature of dilution.
* The process of diluting a concentrated acid (like concentrated sulphuric acid or nitric acid) is highly exothermic, meaning it releases a large amount of heat.
Step 2: Consequence of adding water to acid.
* If water is added to a concentrated acid, the lighter water will float on the surface of the denser acid. The heat generated by the reaction will be localised and intense. This intense heat can cause the water to rapidly convert into steam. Th...
Q6: What is meant by 'water of crystallisation'? Give two examples of salts that contain water of crystallisation and write their chemical formulae.
Step 1: Define water of crystallisation.
* Water of crystallisation refers to the fixed number of water molecules that are chemically associated with one formula unit of a salt in its crystalline state. These water molecules are an integral part of the crystal structure and are responsible for the specific shape and often the colour of the crystals.
Step 2: Provide examples and chemical formulae.
* Example 1: Copper Sulphate (Blue Vitriol)
* When copper sulphate crystallises from an a...
Showing 6 of 10 questions. Visit the full page for complete solutions.